the chinese alphabet is the same as english in written ...A-----Z,but noramlly ,we never use letter "V" in chinese pinyin.as to the pronounciation. you'd better to buy a CD or ask something to teach face to face.
I will show you some exsample.
Aa in chinese pinyin pronunciation,we read as "(a:)" slimiar as the "ar" in "bar"........
i hople it be of help to you.